This photography by jacob riis, entitled, sleeping children. he was a photographer in new york city in the early 1900s who used his camera and skills to capture images in an effort to fuel change for the poor. this type of photography is called

I think the answer is social documentary photography.  Riis wanted to expose the problems caused by urbanization and industrialization.  Many families were living in very harsh conditions.  Through his photographs of the plight of the poor, the government took action and implemented many programs to improve their condition.  Riis also made use of flash photography when taking these pictures.  This made use of a device that brighten the picture.

a chromatic scale uses the twelve tones of the octave, while a regular scale only uses eight, or seven different notes (as the first note is played twice)